The Defender Sentinel 3 consists of a digital video recorder, an LCD monitor and a pack of security cameras. The bullet cameras included with the DVR are suitable for outdoor use, there are eight of them and each one is fitted with a ¼ inch CCD image sensor. You can record video footage in low level lighting with the cameras included with the Sentinel 3, the cameras use an NTSC video signal and have a maximum resolution of 420 TV lines. The bullet cameras have a focal length of 3.66mm, they have automatic white balancing and the outer casing of the cameras is composed of anodised aluminium.

At 8 inches the LCD monitor included with the security recorder is compact, the monitor has a maximum pixel resolution of 480*468, the monitor serves its purpose and you can program it to turn on and off at specific times. Moving on to the DVR the device uses MJPEG compression and you can attach up to eight surveillance cameras to it. The DVR uses G.711 audio compression and is compatible with both PAL and NTSC video signals.

Video recorded by the DVR is stored on its 250 gigabyte internal hard drive, you can swap this out if required, at maximum you can attach hard drives that have up to a 500 gigabyte capacity. When monitoring video footage you can view all cameras attached to the DVR simultaneously on one monitor, you can set the DVR to record when it detects motion and you can attach up to 16 external alarms to the system to control recording.

As you would expect you can also set the DVR to record continuously if required for considerable time, by lowering the systems frame rate you can leave it to record for several months before it starts to overwrite old footage. The maximum recording rate of the DVR is 30 frames per second and you can connect it to a network for the purpose of monitoring and controlling the system remotely. The DVR is fitted with an Ethernet port so you can connect it to a computer network or to the Internet and it is compatible with several network protocols.

The DVR can sound an alarm if it detects a problem with an attached camera, the system also accommodates CF memory cards so you can transfer the surveillance camera footage it records to a PC quickly. When it comes to monitoring activities recorded by the DVR remotely you can do so with Internet Explorer, you can possibly do the same with other web browsers but only IE is supported.